So I decided to open up my latest CPS 1500 and make a guide while I'm at it.It's a CPS 1500 MK II (I'm calling it)... this is the version with the smaller selector plate.

*EDIT* I am no longer sure which is older, I have two CPS 1500 that seem ancient but of different marks, so... yeah. Call it what you will!

For starters, let's review the symptoms.-It won't pump air, the gun will actually pressurize with water just a little bit, about 3 pumps, then the OPRV will kick in with a horrible noise.-The trigger is sitting back a good 1/4" from the normal position, while still pressurize-able. I would guess the outer spring has rusted into oblivion.-So if you pull the trigger back/forth, it will actually open and close the valve. There is just enough friction to prevent it from closing without significant water pressure.-The nozzle screw, and probably spring, is rusted badly and the selector is stuck quite solidly in the 10X position.

This thing had to have been kept UNDERWATER for some time, in order to rust like this!

Anyways, this version has a threaded pump cap and the nozzle cover glued on. So now I go, crap, how am I going to remove this?Well the answer is... carefully, with a flat screwdriver. Here are some pictures:I started with the edge near the selector tab, where there was the least resistance. From there I went around the rim and carefully pried up the edge bit by bit.You don't want to pry too hard or put the blade in too far, or you will simply break the cover into little pieces. Given that these things are ~15 years old, the plastic will be somewhat brittle, so expect the whole thing to crack a little bit, but if you are patient you should be able to crack the glue. I only messed up in one tough spot and made a fairly visible crack.As it turns out, there are no screws underneath the cover on this mark (unlike the other mark of CPS 1500!!!). So if you take all of the screws out first, you may find it's actually easier to twist the shell and detach the nozzle cover (as I remember doing with my CPS 1700). Then again, you might have no luck with this method (like my other CPS 1700).

To Be Continued... tomorrow I will unscrew the gun and take a look inside. So look forwards to part 2 tomorrow!

Last edited by soakinader on Sun May 25, 2014 11:55 pm, edited 1 time in total.

The nozzle selector comes off, along with some black rust.Almost all of the screws in the gun were very rusty.

Add this to my list of times not to use a magnetic screwdriver.Now, to the inside of the beast:This thing is gnarly. This thing is brutally rusted.-The valve is basically rusted shut. With 12, untouchable screws.-The trigger backspring has rusted into oblivion. I found a few splinters of it rattling around the casing.-The outer valve spring was so rusty, it broke in two.

The whole thing is just nuts.

And you know the worst part? I don't even think that I have gotten to the problem yet. The firing valve seems OK, it's just that either the PC is too stiff/clogged full of who-knows-what, or the OPRV is damaged and opens too "easily".... and I say that because, hey, there's nothing easy about pumping it. I remember my SC 500's had a very stiff PC, and you had to have A: an excellent pump seal and B: a lot of pressure in order to fill them. This thing is crazy rusty, but honestly I don't know what the problem is.Thoughts?

Last edited by soakinader on Sun May 25, 2014 11:58 pm, edited 1 time in total.

So this thing has a lot of rusty screws! The firing valve alone has 12 screws, and the PC casing has 19. Anyways...I don't think there is anything wrong with the PC.But hey- just for fun, since I'm working on a CPS 1-3-5 and a 1500 at the same time, I'll try using the 1-3-5 PC in the 1500.

And the result- the same problem. As far as I can tell, the pump fills the valve and PC just enough that the water begins to get pressurized by the rubber in the PC. At that moment, the OPRV opens up and water floods into the PC.It's like this thing was k-modded with too many balloons (or rubber bands).

So this thing has a really weak/damaged OPRV, just as I thought. The question is, how do I fix that? I'll probably have to cut the valve, but preferably I would like to know what is wrong rather than just cut/drill and glue.

In the interest of not having more bursted bladders, I posted another comment on that page on how using rubber bands will break them.

The 1500 is known to have a weak pressure relief valve. A number of blasters have this problem, with what is referred to as HPL. The CPS 1200 and certain marks of the 2100 have good HPL, where you can k-mod about 30-40 balloons or so without the PRV going crazy. The 1000 has about average HPL, where you can only use about 20 and/or can't pump too fast. Sometimes, PRV's will partially release and make noise while pumping, but still allow some pressure to be built. (This happens a LOT on the CPS 1000.) The 2100 mk II, 1500, 2700, and others all have poor HPL and will not be receptive to modding.

From there, the only option is to gut the PRV, which theoretically gives you a higher balloon limit. However, too much pressure, and you risk damaging the pull valve. From this, I'm working on solutions that involve homemade internals, including a ball valve that won't have pressure limit concerns. (This may be the only way to house a 95-balloon k-mod.)

It's also possible to mod the PRV. There have been reports of people doing this, who don't document the process. It seems that the general procedure is to cut the valve open, replace the spring and/or move parts around, and them use all the epoxy in the world to seal it back up. Personally, I'd just gut the thing if I had to at that point.

Sooo yeah... I removed the pressure release valve (PRV) and.... well let's see how I did it!

First cut all the way through the narrow end with a trusty hacksaw. I cut flush with the plastic. Then cut at the other side...For the other end, if you don't care about destroying the rubber gasket, you will actually want to cut about one blade's width (or ~1/16") away from the base. With a bit of luck, you could actually cut straight through while avoiding the spring and gasket entirely. Me, I cut flush but when I realized that I had hit something black and rubbery, I stopped using the hacksaw, grabbed my trusty exacto knife, and sliced upwards, avoiding the gasket. Then I twisted the valve and...The valve snapped right out.

So there's the problem. This spring is pathetic. The one in my Vaporizer was stronger! Anyways, I imagine that this is the cause of all of my problems. So... I think I will cut a piece of PVC, and cap off the ends+shove it in between in order to seal up the gap, plus this will help withstand the pressure a tiny bit. Or, if I can find a stronger spring that fits, I might just try putting the valve back! I don't see why not.

I guess I should mention that I have no interest in K-modding, ESPECIALLY after putting all 19 of those damned screws back into the PC casing.Still ticks me off though, that this thing was basically defective and failing ever since it was made.

More pics on my minus page. Check em out while you can.

*EDIT* So I found a stronger, longer spring that I will use in the check valve. The only thing that can go wrong is that the spring is too strong and won't open before the PC explodes; however this would still be better than no PRV at all. Well, the spring could also be too weak and I could be back to square one, but I don't think so.I also have a replacement spring for the trigger. Not sure what I can do about the one on the back of the valve- actually, I could cut the rusted one off and twist a new one on... I'm certain I have done that once before. That sounds like a good idea! I'll look into that tomorrow.

Looking good! The best feeling is when you take a gun that is extremely broken and completely heal it back to brand new. Don't settle for anything but perfect on this one! I've had fun reading this thread... gets me pumped for my next war!

Replacing the back valve spring:This spring might be rusty and useless, but it's strong. I had to take a pair of needlenose pliers and take it apart bit by bit. The result was a rusty mess with little spring fragments. You can see the replacement spring just above the old.

Now for the new (cut) spring:Just twist it on there, starting at the middle where it is thinnest. Use your pliers, if your spring is tough like mine was.And we're done. I later shortened this spring to allow the firing valve to close properly.

Last edited by soakinader on Fri Jun 20, 2014 12:58 am, edited 1 time in total.

So I've glued the OPRV back in with a new spring...I started by marking the position of the piece with a permanent marker. Since I snapped the piece out, there is considerable structure to one side of the valve. As for the rest of the valve, I will need to fill it in with JB Weld. I used a pin to hold the valve in the correct position while the JB weld on the other side dries. I later added some JB weld around the pin, and once that dries I should be able to remove the pin and fill the rest of the gap up. Hopefully this solves a problem without creating another one!

The JB Weld had plenty of time to dry, so I closed the CPS 1500 and tested it. After some initial pump-shooting, I shortened the back valve spring a little. The result:[Insert cool shot picture here]It works perfectly! BTW, without the nozzle selector, it has some serious recoil. That's how I like it!

The new OPRV works, although the pump gets very hard and the water flows very little through the valve. That's probably because the spring I replaced is the same length, but very tough. I have a strong feeling that the rubber gasket for this CPS 1500 was installed backwards, and that was the cause more than anything. But anyways, you aren't going to notice this very often at all! It pumps up and shoots beautifully.I have to say, this was the rustiest gun I have ever fixed. But I managed to take this neglected, broken gun for 6$, put in a few hours of labour and the end result is a golden piece of CPS super soaker. And I have good feeling that this is my most powerful CPS 1500 yet!

Ihave a lot on at the moment and soakers are not on my list but do you think Is should pay up? It would mean that I have not only a working ss 1500 but one that had been ressurected to drecnh another day which is always good. ALso the chances of finding a working one with no issues for less than than is virtualy zero.